Control for machine tools



July 22, 1969 A. R. HENRY CONTROL FOR MACHINE TOOLS Filed July 20, 1967 I NVENTOR Awe/f P. Hen/y Z W YJ%WORNEY5 United States Patent 3,456,466 CONTROL FOR MACHINE TOOLS Albert R. Henry, Salina, Kans., assignor to Henry Industries, Iuc., Salina, Kans., a corporation of Kansas Filed July 20, 1967, Ser. No. 654,810 Int. Cl. B21j 7/26, 7/46; B30b 15/00 U.S. Cl. 72-26 7 Claims ABSTRACT OF THE DISCLOSURE A safety system for a machine press or the like operable to avoid damage to the tools, the dies, and the work being punched, sheared, bent or formed, by adjustably limiting the stroke of the tool carrier through a lost motion assembly operably interconnecting the carrier and a control for its prime mover.

It is the primary object of the instant invention to provide an arrangement between the prime mover (such as a hydraulic piston and cylinder assembly) of a tool carrier and the control for the prime mover (such as a valve) which will return the valve to a neutral position automatically each time the valve is actuated, to either raise or lower the tool, all through adjustable, limiting stop means, so as to predetermine the stroke of the tool carrier and thereby avoid the aforementioned damage experienced through use of machine tools generally.

In the drawing:

FIGURE 1 is a perspective view of a control for machine tools made pursuant to my present invention; and

FIG. 2 is a fragmentary, rear elevational view of the valve supporting shelf and associated parts.

A stand 10* provided with a plurality of legs 12 supports a prime mover 14 in the nature of a double acting hydraulic piston and cylinder assembly through the medium of a standard 16. The vertically reciprocable piston rod of assembly 14 is designated by the numeral 18 and is adapted to support a tool such as a punch, through the medium of a tool carrier 20 thereon for movement toward and away from a die 22 on top 42.

The prime mover 14 is controlled by a valve 24 having a vertically reciprocable actuating device 26 operable to direct hydraulic fluid toward and away from the prime mover 14. In this connection, the hydraulic fluid under pressure flows into the valve 24 by way of line 28 and thence to the fluid storage tank by way of line 30 when the valve stem 26 is in its neutral position. Raising of the valve stem 26 directs the oil from line 28 into line 34 leading to the bottom of the cylinder of assembly 14 to raise the piston rod 18 and conversely, lowering of the valve stem 26 directs the oil to the top of such cylinder by way of line 32 to lower the piston rod 18.

The valve stem 26 may be raised and lowered through use of either of a pair of manually manipulable members, including a hand lever 36 and a foot pedal 38. Valve 24 is supported by a shelf 40 depending from the top 42 of stand 10, shelf 40 also supporting the lever 36 for up and down swinging movement through the medium of the bracket 44. A spring 46 between shelf 40 and lever 36 yieldably biases the lever 36 toward one end of its swinging movement.

The foot pedal 38 is rigid to and extends laterally from a rock shaft 48 carried by a pair of the legs 12, and a link 50 pivotally interconnects the lever 36 with the foot pedal 38.

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Structure broadly designated by the numeral 52 and operably connected with the piston rod 18 for vertical reciprocation therewith includes a rod 54 vertically reciprocable within a sleeve 56 mounted on top 42 and an arm 58 which interconnects the rods 18 and 54 through the medium of adjustable clamps 60 and 62.

In addition to the rock shaft 48, mechanism broadly designated by the numeral 64 for operably connecting structure 52 with the control 24 includes a lost motion assembly 66. A vertical element 68 in the nature of a bolt is carried by the rod 54 by use of an adjustable clamp 70 and a connecting arm 71. Bolt 68 passes through a crank 72 rigid to the shaft 48, crank 72 being disposed between a pair of stops 74 and 76 in the nature of nuts on the bolt 68.

In operation, when the pedal 38 is depressed valve stem 26 is lowered to in turn lower the tool carrier 20. This in turn lowers the rod 54 as well as the bolt 68, causing the nut 74 to engage the crank 72, thereby rocking the shaft 48 and raising the valve stem 26 to the neutral position.

Conversely, when the hand lever 36 is raised to raise the stem 26, tool carrier 20 moves away from the table top 42, causing the rod 54 to be elevated. Bolt 68 rises as it moves loosely through the bracket 72 until the nut 76 rocks the shaft 48 through the crank 72 so as to lower the stem 26 to its neutral position through the link 50.

It can now be appreciated that by adjustment of the nuts 74 and 76 on the bolt 68 the stroke or travel of the piston of the assembly 14 can be accurately controlled so as to stop the travel of the tool at the right place at all times without damage to the tools or to the work being punched, sheared, bent, formed or the like and without damage to such dies as may be used in connection with the machine operations.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In a machine tool:

a reciprocable tool carrier;

a prime mover connected with said carrier for reciprocating the latter;

a control connected with said prime mover having a shiftable multiple-position device, including a first position for initiating movement of the carrier in one direction, a second position for initiating movement of the carrier in the opposite direction, and a neutral position;

structure connected with said carrier for reciprocation therewith; and

mechanism interconnecting said structure and said device for shifting the latter to said neutral position after travel of said carrier a predetermined distance in either direction.

2. The invention of claim 1,

and a manually manipulable member attached to said device for shifting the same to said first or to said second position,

said mechanism being connected to said member.

3. The invention of claim 2,

said mechanism including a lost motion assembly for preventing transmission of movement to said structure from said member upon actuation of the latter.

4. The invention of claim 3,

said assembly being provided with means for varying the stroke of said carrier.

5. The invention of claim 1,

said structure including a rod joined with the carrier for reciprocation therewith,

said mechanism including a rock shaft, and a lost motion assembly interconnecting the shaft and the rod for permitting limited reciprocation of the rod without rocking of the shaft by the rod.

6. The invention of claim 5,

said assembly including an element joined with the rod for reciprocation therewith, a pair of spaced stops on the element, and a crank swingable on the element between the stops,

said crank being secured to the shaft for rocking the latter when the stops engage the crank to swing the latter.

7. The invention of claim 6,

said element comprising a bolt and said stops compris- 4 ing nuts movable on the bolt toward and away from each other.

References Cited CHARLES W. LANHAN, Primary Examiner G. P. CROSBY, Assistant Examiner US. Cl. X.R. 

